Superheater.



Nn. 642,23I, Patentedrlan. 30, |900. A. U. JAASTAD.

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No. 642,23l. Patented 1an. 30, i900.

A. U. JAASTAD.

SUPERHEATER.

(Application led Sept. 25, 1899.) (No Muriel.) 2 SheetS--Shet 2.

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nire STATES PATENT lemon.

AMUND .TAASTAD, OF BOSTON, MASSACHUSETTS.

SUPERHEATJER.

SPECIFICATION forming part of Letters Patent 10.642,231, dated January 3o, 1900.

Application led September 25, 1899. Serial No. 731,552. (No model.)

.To all whom it may concern:

Be it known that I, AMUND U. JAAs'rAD, of Boston, county of Suffolk, and State of Massachusetts, have invented an Improvement in Superheaters, of which the following description, in connection with the accompanying drawings, is a specification, like letters on the drawings representing like parts.

The present invention relates to a superheater for boilers, one obj ect of the invention being to so construct the superheater that it can be easily attached to exist-ing boilers without modifying the construction thereof and without interfering with the ordinary use of the boiler if the superheater is out of order and requires repairs.

A further feature of the invention consists in so arranging the superheaterthat it is readily accessible for repairs even when the boiler is in operation and also so that it is not acted upon by the gases until they have reached a point where they are about to leave the boiler and have given up the greater part of their heat in converting the water into steam.

The invention is herein shown as applied to a Babcock d: Wilcox water-tube boiler, although it may obviously be applied to boilers of other types.

In accordance with the invention the superheater comprises a continuous series of tubes arranged in any suitable or usual way and contained in the chamber below the steamdrums, said tubes occupying that part of the chamber which is between the boiler-tubes and the draft-outlet, so as not to be acted upon by the gases until after they have left the last pass in the boiler.

The superheater is shown as having two sections, each of which is provided with a pair of headers, one of which forms the inlet and the other the outlet, and the inlet-headers are arranged to be directly coupled to the cross connection which connects together the several steam-dru ms when, as is usually the case, there are two or more of such drums all connected with the same system of watertubes. The said cross connection for the steam-drums is usually provided with an inlet from each drum and a common outlet, from which the steam is taken to the place where it is to be used, and the superheater embodying the present invention is arranged to have its inlet and outlet passages connected with the said steam-outlet, with Valves interposed, so that the steam can be caused to pass through the superheater or be taken directly from the boiler or partly from each,l as may be desired. It is only necessary, therefore, to connect with the ordinary steam-out let of a boiler a coupling containing a Valve and a branch connection beyond the said valve, having two inlets and a single outlet, one of the said inlets being connected with the superheater and the other with the coupling aforesaid, which is connected with the main outlet-passage from the boiler. The superheater itself is provided with valves at both its inlet and its outlet end, the latter valve being interposed between the said branch passage and the tubes of the superheater, so that by closing the said valves the superheater can be completely cut off and the steam allowed to pass directly from the boiler by opening the boiler-valve.

Vater-tube boilers of the Babcock da TilcoX make or similar type as commonly constructed are provided with a series of battles whereby the products of combustion are caused to pass upward across the tubes and thence downward and again upward, the spaces between the said baffles being usually designated as the first, second, and third passes, there being commonly two baffles and three passes.

The superheater-tubes in accordance with the presentinvention are located in or beyond the third pass, (or, if there are more than three passes, in or beyond the last pass,) so as not to be acted upon bythe gases until the heat has been largely extracted therefrom and used in converting the water into steam. As herein shown, provision is made for flood ing the su perheater, or, in other words, filling the superheater-tubes with Water when the boiler is first started, (to be afterward drawn off 5) but such ooding is not essential with this construction, since the heat Will be so greatly reduced before reaching the superheater-tubes that there is practically no danger of burning out the superheater.

Figure 1 is an elevation, partly in section, of a superheater embodying the invention shown as applied to a Babcock dt VVilcoX boiler, the section being mainly taken on the IOO line Qc of Fig. 2. Fig. 2 is a transverse section of the same, taken on theline m2 of Fig. l, the outlet connections being omitted from Fig. 2. Fig. 3 is a partial top plan view of the boiler', showing the end Where the superheater is placed. Figs. 4 and 5 are details to be hereinafter referred to; Fig. 6, a vertical section showing a modification in which the superheater is applied to a boiler having only two Waterdrums; Fig. 7, a partial top plan view of the same; and Figs. 8, 9, and 10, sectional views showing further modifications, Fig. 8 being a section on the line 008 of Fig. 9, Fig. 9 a horizontal section on the line 009 of Fig. S, and Fig. 10 a vertical section on the line m10 of Fig. 8.

. As shown in Fig. l, the Water-drums A, which in this type of boiler also constitute the steam-chambers, are each provided with an outlet-passage A2, which connects with a single outlet A3 through a cross connection A4. This is the common construction in boilers of this type, and the connection is made in substantially the same way to a common steam-outlet without regard to the number of Water-drums which are used.

In accordance with the present invention the superheater is so arranged that its inlet portion can be readily connected to one or both ends of said cross connection, while its outlet portion is connected to one branch of a double inlet coupling-piece,the other branch of which is arranged to be connected directly with the boiler-outlet, thesaid coupling, however, being provided with a valve in each branch.

The superheater is preferably made in two parts, each of which is the duplicate of the other, the inlet of one part being coupled Vto one end of the cross connection A4, and the inlet of the other part being coupled to the opposite end of said cross connection, while the outlets of said parts are both connected With the coupling aforesaid, the object of this arrangement being mainly to obtain a more symmetrical arrangement and greater heating-surface for the superheating-tubes. Y A

Referring to Figs. l and 2, the superheater embodying the invention comprises an inlettube Ct, provided with a valve b, arranged to be coupled directly to the end of the cross connection A4, so that when the valve h is op'en the steam will pass from the boiler into the said inlet-tube a, which terminates in the header aiand thence through a series of tubes a3 to an outlet-header (t4, which is coupled in any suitable or usual way with the main steam-outlet from the boiler.

As herein shown, the parts above described are duplicated, there being an inlet tube connected with each end of the cross connection A4, the several tubes a3 overlapping and being staggered, as shown, While the outlettubes CL4 are connected with a cross-tube a5, which is arranged to be connected with the main steam-outlet through the coupling-piece c, which is provided with two inlets and a single outlet c2. The said coupling itself is arranged to have one-of its branches connected With the main boiler-outlet A3, as best shown in Fig. l, and the boiler-outlet and the superheater-outletv are respectively controlled by means of suitable valves d and e, it being obvious that when the valve d is closed the steam from the boiler cannot pass directly to the outlet c2, but must pass into the inlet-pipes a, and thence through the superheater, which thus practically constitutes a by-pass. If, on the contrary, the valve d is open and the valve e closed, the steam will pass directly from the boiler tothe outlet, and in order to cut off thev superheater entirely from the boiler it is necessary only to close the valves b, so that no steam can pass into the superheater at either end thereof. Assuming, therefore, that the superh eater is in use, the steam will pass from the tube a4 through the valves b into the tubes ct, and thence across the chamber below the steam-drum, and upward to the cross-tube a5 through the valve c to the outlet c2. If, however,anything happens to the su perheater so that it requires repairs or if its use would be otherwise detrimental or undesirable, itis necessary only to shut the valves b and the valve e and open the valve d, in which case the steam will pass directly from the boiler to the outlet, so that there is no necessity for shutting down the plant pending repairs. Furthermore, .it may in some cases be desirable to use both saturated and superheatedA steam, and it is obvious that the valve d affords means for permitting any desired amount of steam direct from the boiler to mix with the superheated steam. 'lo facilitate regulation, the valve d is shown as having a small by-pass d2, provided with a valve d3, so that the regulation can be easily and accurately accomplished.

AS best shown in Fig. l, the superheater is `contained in that portion of the chamber be- IOD IIO

may be more readily removable when repairs with the pipe g, connected with the waterdrums or other source of water-supply and controlled by a valve g2, so that the superheater-tuhes may bc flooded, if desired, when the boiler is started up, the said tube g being provided with another valve g3 for drawing off the water after steam is actually gcnerated. The flooding in this case, however, is not essential, but is only provided for as a safeguard, since the heat of the gases will be so far reduced bythe time they reach the superheating-tubes that there will be no danger of burning out the superheater.

From the foregoing description it will be seen that a snperheater embodying the present invention can be easily applied to boilers of existing types without modification in the boiler itself or its connections. The valves b, d, and c and the coupling c form a part of the superheater and may be readily connected to the cross connection and the main steamoutlet of the boiler, respectively, while after the superheater is connected the boiler may be used with or without the superheater, as may be desirable or necessary.

It is obviously not essential that the superheater should be arranged as shown in Figs. 1,2, and 3, since it may be desirable in some cases to provide for a larger heating-surface in the same space or to arrange the superheater for use with a boiler having a different number of water-tubes. Fig. 5 shows in detail a pair of headers in which a number of small tubes are arranged in two rows along each header instead of a single row, as shown in Fig. d.

As shown in Figs. G and 7, for example, the superheater is applied to a boilerhaving only two drums, the only difference in this case being that the outlet-headers are adjacent to each other and terminatein a common coupling-piece @30 instead of cross-tube as, the said coupling-piece being arranged to be connected with one branch of the coupling c.

in Figs. S, E), and lO the headers are arranged substantially as shown in Figs. G and 7; but the tubes d3 are curved in order to obtain a greater heating-surface, the outletheaders being adjacent to each other and communicating with a coupling a3, as before.

It is not intended to limit the invention to the specific construction herein shown and described, since modifications may obviously be made without departing from the invention.

I claim-- l. A superheater for boilers comprising a system of tubes located in the boiler; inlet and outlet tubes connected with the said tube system and extending therefrom to a point outside the boiler; couplings for said tubes whereby they are adapted to be connected to the steam-passage at a point outside the steam-drum; and valves respectively controlling the said superheater and the said steam-passage, substantially as described.

The herein-described superheater which comprises a set of tubes extending transversely across the boiler and located above the boiler-tubes and beyond the last baffleplate; and inlet and outlet passages connected with said tubes and adapted to be connected with the steam-outlet from the boiler at a point outside the steam-drum, as set forth.

3. A superheater comprising an inlet-passage provided With a valve adapted to be coupled directly with the steam-outlet from the boiler at a point outside of the steamdrum; a series of superheating-tubes leading from the said inlet-passagethrou gh the boiler; an outlet-passage connected with the steamoutlet at a point outside of the steam-drum; and a valve in the steam-outlet interposed between the inlet and outlet passages of the superheater, as set forth.

4E. A superheater comprising an inlet-duct adapted to be connected with the end of the cross connection which connects the waterdrums of the boiler with the main steam-outlet; steam-passages extending from said inlet-duct transversely across the heat-chamber in the boiler; an outlet-duct extending from the opposite ends of said steam-passages to 'a coupling connected with the boiler-outlet,

said coupling having two branches each provided with a valve, one connected directly with said boiler-outlet and the other with the superhcater-outlet; and valves controlling the superheater-inlets, substantially as described.

5. A superheater having its inlet and outlet duets coupled with the boiler-outlet at a point outside of the steam-drum, and a main valve in said boiler-outlet between said ducts, whereby a direct outlet may be afforded from the boiler, as set forth.

6. A superheater having its inlet ducts coupled to the cross connection outside of the steam-drum and its outlet-ducts coupled to the main steam-outlet beyond said cross connection 5 a main valve in said main steamoutlet between said ducts; and a by-pass valve controlling a by-pass around said main valve whereby saturated and superheated steam may be used at the same time and the proportions regulated, substantially as described.

7. A superheater comprising substantially vertical headers connected together by substantially horizontal tubes, said tubes extending transversely through the boiler above the water-tubes and below the drum; inlets coupled to the ends of the drum cross connection and extending to the outer headers of the superheater; outlets from the inner headers of the superheate'r extending between the steam-drums to one bf the inlets of a branch connection having two inlets and one outlet, the other inlet thereof being connected to the main steam outlet from the steam drums; and a yalve in said main steam-outlet, substantially as described.

8. A superheater having inlets c and out- IOO lets CL4; couplings for saidinlets provided with Valves b at the ends of the cross connection A4; a branch connection c having one of its inlets communicating with the superlieateroutlet a4 and its other inlet communicating with the steam-outlet A3; and the valves d' and e contiolling the inlets of said branch connection, as set forthi In testimony whereof I have signed my name to this specification in the presence of ro two subscribing witnesses.

AMUND n. JAAsTAD.

Witnesses:

NANCY P. Fone, HENRY J. LIVERMORE.- 1 

